Stimulation needle apparatus and method

ABSTRACT

In various examples, a stimulation needle apparatus is used for selectively administering a trial stimulation to body tissue of a patient. The stimulation needle apparatus includes a cannula assembly including a cannula and a cannula hub disposed at a proximal cannula end. A stylet assembly includes a stylet sized and shaped to fit within a cannula lumen. A stylet hub is disposed at the proximal stylet end and is configured to engage with the cannula hub. With the stylet hub engaged with the cannula hub, the distal stylet end extends distally from the distal cannula end. A stylet connection is electrically coupled with the stylet and is configured to electrically couple with a stimulator device, such that, a stimulation pulse delivered by the stimulator device is conducted from the stylet connection through the stylet to the distal stylet end to administer the trial stimulation.

PRIORITY DATA

The present application is a Continuation of non-provisional U.S. patentapplication Ser. No. 15/430,061, filed on Feb. 10, 2017, now issued asU.S. Pat. No. 10,244,956, which is a utility application of provisionalU.S. Patent Application No. 62/294,394, filed on Feb. 12, 2016, entitled“STIMULATION NEEDLE APPARATUS AND METHOD,” the disclosures of each whichis hereby incorporated by reference in their respective entireties.

TECHNICAL FIELD

The present invention relates to a stimulation needle, and morespecifically relates to a stimulation needle for performing one or moretrial stimulations of a nerve or other body tissue.

BACKGROUND

Previous sacral nerve stimulation needles typically include a styletremovably disposed within a cannula, wherein a stylet hub is press fitor snapped into engagement with a cannula hub to locate the stylet inplace within the cannula. A proximal end of the cannula includes a firstuninsulated portion (distal from the cannula hub) for temporaryattachment to a stimulator device in order to perform trial stimulationsin a patient or other subject. The trial stimulations are delivered tothe patient or other subject from a second uninsulated portion at adistal end of the cannula, the second uninsulated portion being spacedfrom the first uninsulated portion.

Previous sacral nerve stimulation needles include several disadvantages.One such disadvantage is with removal of the stylet from within thecannula. In order to remove the stylet, one must grip the cannula withone hand and pull on the stylet hub with the other hand, creating forcesin opposing directions (distally and proximally) and potentially causingthe cannula to move with respect to the patient or other subject,thereby potentially losing the optimal stimulation position. Anotherdisadvantage of previous sacral nerve stimulation needles is that, byclipping the stimulator device to the proximal end of the cannula fortrial stimulations, the overall working length of the needle isdecreased because at least the first uninsulated portion at the proximalend of the cannula must be exposed in order to attach the stimulatordevice to the cannula.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a stimulation needle apparatus in accordancewith at least one example of the invention, the stimulation needleapparatus including a stylet assembly engaged with a cannula assembly.

FIG. 2 is an exploded side view of the stimulation needle apparatus ofFIG. 1.

FIG. 3 is a perspective view of the stimulation needle apparatus of FIG.1 with the stylet assembly partially separated from the cannulaassembly.

FIG. 4A is a side perspective view of the stimulation needle apparatusof FIG. 1 with the stylet assembly being inserted into the cannulaassembly.

FIG. 4B is a side perspective view of the stimulation needle apparatusof FIG. 1 with the stylet assembly being engaged with the cannulaassembly.

FIGS. 5A and 5B are side perspective views of a connector and astimulation device for use with the stimulation needle apparatus of FIG.1 to perform a trial stimulation.

FIG. 6 is a side perspective view of a ground pad and a stimulationdevice for use with the stimulation needle apparatus of FIG. 1 toperform a trial stimulation.

FIGS. 7A and 7B are side perspective views of a stimulation needleapparatus in accordance with at least one example of the invention, astylet assembly being removed from a cannula assembly of the stimulationneedle apparatus during a procedure on a patient or other subject.

FIGS. 8A-8B are side perspective views of a directional guide inaccordance with at least one example of the invention, the directionalguide being inserted into the cannula assembly of FIGS. 7A and 7B duringa procedure on a patient or other subject.

FIGS. 9A-9B are side perspective views of the cannula assembly of FIGS.8A and 8B being removed from the directional guide during a procedure ona patient or other subject.

DETAILED DESCRIPTION

Stimulation needles can be used to perform one or more test stimulationsat one or more locations within a patient or other subject to assist inlocating a proper position for a medical device, such as, for instance,a stimulation lead, within the patient or other subject. The examples ofthe present invention described herein seek to overcome the shortcomingsof the previous sacral nerve stimulation needles.

The present patent application relates to stimulation needle apparatusesand methods. In various examples, as described herein, the stimulationneedle is configured to allow for trial stimulations within the patientor other subject in order to determine an optimal or otherwise desirablelocation for an implantable device, such as, but not limited to, astimulation lead, within the patient or other subject.

Although described with respect to positioning proximate and performingtrial stimulations with respect to a sacral nerve, it should beunderstood that the present invention can be used with other nervesand/or body tissue and/or to position various types of medical deviceswithin the patient or other subject.

Referring to FIGS. 1-4B, in some examples, a stimulation needleapparatus 100 is configured to access body tissue of a patient 10 orother subject (see FIGS. 6-9B). In some examples, the stimulation needleapparatus 100 is configured to selectively administer a trialstimulation to the body tissue of the patient 10 or other subject. Insome examples, the stimulation needle apparatus 100 includes a cannulaassembly 120 and a stylet assembly 140 removably coupled with thecannula assembly 120. The stimulation needle apparatus 100, in someexamples, is configured to pierce, puncture, or otherwise extend throughbody tissue in order to be positioned at a desired location within thepatient 10 or other subject. In some examples, the stimulation needleapparatus 100 is configured to be inserted through body tissue andthrough a sacral foramen in order to access a sacral nerve with thestimulation needle apparatus 100.

In some examples, the cannula assembly 120 includes a cannula 122. Insome examples, the cannula 122 includes a tubular shape having a cannulalumen 123 extending from a proximal cannula end 122A to a distal cannulaend 122B. The cannula 122, in some examples, is insulated. For instance,in some examples, the cannula 122 is formed from one or more insulativematerials. In other examples, the cannula 122 is formed by one or moreconductive materials and coated, covered, or otherwise including one ormore insulative materials disposed on an exterior surface of the cannula122. In this way, in various examples, the cannula 122 is configured toinsulate the body tissue of the patient 10 or other subject from astimulation pulse conducted within the cannula.

In some examples, the cannula assembly 120 includes a cannula hub 126disposed at the proximal cannula end 122A. In some examples, the cannulalumen 123 is accessible through the cannula hub 126. In furtherexamples, the cannula hub 126 can include a passage therein with accessto the cannula lumen 123. That is, in some examples, an opening at theproximal cannula end 122A is open and accessible through a proximal endof the cannula hub 126, for instance, to allow fluid communicationthrough the cannula hub 126 to the cannula lumen 123. In some examples,the cannula hub 126 is engaged with the cannula 122. For instance, in anexample, the cannula hub 126 is molded onto the cannula 122. In anotherexample, the cannula hub 126 is integrally formed with the cannula 122.For instance, the entire cannula assembly 120, in some examples, can bemolded.

In some examples, the cannula 122 includes one or more depth marks 124on an exterior surface of the cannula 122. In some examples, the depthmarks 124 are printed on the cannula 122. In some examples, the depthmarks 124 are etched, molded, or otherwise formed into the cannula 122,either instead of or in addition to being printed on the cannula 122.The one or more depth marks 124, in some examples, can be used todetermine a depth at which the cannula 122 and, in turn, the stimulationneedle apparatus 100 are inserted into the patient 10 or other subject,as will be described in more detail herein. In some examples, the one ormore depth marks 124 can be used to determine a depth of insertion ofthe stimulation needle apparatus 100.

In some examples, the stimulation needle apparatus 100 includes a styletassembly 140. In some examples, the stylet assembly 140 includes astylet 142 sized and shaped to fit within the cannula lumen 123. In someexamples, the stylet 142 includes a proximal stylet end 142A and adistal stylet end 142B. The stylet assembly 140, in some examples,includes a stylet hub 146 disposed at the proximal stylet end 142A. Insome examples, the stylet hub 146 is configured to engage with thecannula hub 126. In some examples, the stylet hub 146 engages with thecannula hub 126 with a twist engagement. For instance, in some examples,the stylet hub includes one or more stylet threads 148 configured tomateably engage with one or more cannula threads 128 of the cannula hub126. For instance, in some examples, referring specifically to FIGS. 4Aand 4B, the stylet 142 can be inserted within the cannula 122 and thestylet assembly 140 moved distally with respect to the cannula assembly120 along a direction A and rotated along a direction B to engage theone or more cannula threads 128 with the one or more stylet threads 148(FIG. 3), thereby engaging the stylet hub 146 with the cannula hub 126.To disengage, the stylet assembly 140 can be rotated in a directionopposite to direction B and the stylet assembly 140 moved proximallywith respect to the cannula assembly 120 along a direction opposite todirection A.

Such a configuration allows for engagement and disengagement of thestylet assembly 140 and the cannula assembly 120 using relativerotational motion. In this way, the likelihood of the cannula assembly120 migrating proximally or distally during engagement or disengagementof the stylet assembly 140 and the cannula assembly 120 is reducedbecause the forces imparted to the stylet assembly 140 and/or thecannula assembly 120 for engagement or disengagement of the styletassembly 140 and the cannula assembly 120 are largely rotational andlargely not directed longitudinally (proximally or distally) withrespect to the stylet assembly 140 and/or the cannula assembly 120.Although threaded engagement between the stylet assembly 140 and thecannula assembly 120 is shown, in other examples, other types ofrotational engagement are contemplated, such as, but not limited to, atab-in-slot connection, a bayonet connection, and a compressioncoupling. In other examples, non-rotational engagement of the styletassembly 140 and the cannula assembly 120 can be used, such as, forinstance, a press fit configuration and/or a snap-togetherconfiguration.

The stylet 142, in some examples, is electrically conductive to allow anelectrical pulse to be conducted along the stylet 142. In some examples,the stylet is formed from a metallic material. In some examples, thedistal stylet end 142B includes a pointed tip 142C. In some examples,the pointed tip 142C is configured to pierce, puncture, or otherwisepass through tissue, for instance, to insert the stylet 142 within apatient 10 or other subject. In some examples, with the stylet hub 146engaged with the cannula hub 126, the distal stylet end 142B extendsdistally from the distal cannula end 122B. In further examples, thepointed tip 142C extends distally from the distal cannula end 122B withthe stylet hub 146 engaged with the cannula hub 126, for instance, tofacilitate piercing, puncturing, or otherwise passing through tissue,for instance, to insert the stimulation needle apparatus 100 within apatient 10 or other subject.

In some examples, the stylet apparatus 140 includes a stylet connection150 electrically coupled with the stylet 142. In some examples, thestylet connection 150 is disposed at a proximal portion of the stylethub 146 and configured to electrically couple with a stimulator device180 (see FIG. 5A). Having the stylet connection 150 disposed proximal tothe stylet hub 146 is an improvement over the conventional designsdescribed above having first and second spaced-apart uninsulatedportions, both distal the stylet hub. With the present design, there ismore effective length of the stylet 142. In some examples, with thestimulator device 180 electrically coupled to the stylet connection 150,a stimulation pulse delivered by the stimulator device 180 is conductedfrom the stylet connection 150 through the stylet 142 to the distalstylet end 142B to administer the trial stimulation to the patient 10 orother subject. In some examples, the stylet connection 150 extendsproximally from the stylet hub 146. In some examples, the styletconnection 150 includes a loop. In some examples, the stylet connection150 is integrally formed with the stylet 142. For example, the stylet142 can extend through the stylet hub 146 and proximally from the stylethub 146 to form the stylet connection 150, such that the stylet 142 andthe stylet connection 150 are integrally formed from the same piece ofmaterial. In other examples, the stylet connection 150 can beelectrically coupled to the stylet 142 with a conductor disposed betweenthe stylet connection 150 and the stylet 142. In some examples, theconductor can include a wire or other conductive member. In someexamples, the conductor can include a material different from thematerial or materials from which at least one of the stylet 142 and thestylet connection 150 are formed.

Referring to FIGS. 5A and 5B, in some examples, the stylet connection150 is configured to be selectively coupled to a connector 160, such as,but not limited to a test clip 160. In other examples, a connector otherthan a test clip can be used, such as an alligator clip, a pin andsocket connector, a threaded connector, or the like. In some examples,the test clip 160 includes a body 162 with a conductive hook 164extendable from the body 162. For instance, the conductive hook 164 canbe extended from within the body 162 (by pushing button 165, forinstance) (FIG. 5A) and then attached to the stylet connector 150 (FIG.5B). With the test clip 160 attached to the stylet connector 150, thetest clip 160 can be electrically coupled to the stimulator device 180.In some examples, the test clip 160 includes a wire 166 for electricallycoupling the test clip 160 to the stimulator device 180. In someexamples, the wire 166 includes a plug 168 or other connector forcoupling to a socket 188 or other mating connector of the stimulatordevice 180. In other examples, the wire 166 is configured to couple toat least one intermediate device between the test clip 160 and thestimulator device 180. For instance, in an example, the wire 166includes a pin or other connector configured to couple with a trialconnector or other device which, in turn, is coupled to the stimulatordevice 180.

Referring to FIG. 6, in some examples, a ground device 170 can beattached to the patient 10, for instance, on the heel of a foot 12, inorder to complete the circuit to allow for a trial stimulation to beadministered. In some examples, the ground device 170 includes a groundpad 172 configured to be adhered or otherwise placed in contact withskin of the patient 10. In some examples, the ground device 170 furtherincludes a wire 174 extending from the ground pad 172, the wire 174including a plug 176 or other connector for mateably engaging with asocket 186 or other connector of the stimulation device 180 in order toelectrically couple the ground device 170 with the stimulation device180.

Once the ground device 170 is attached to the patient 10 and coupled tothe stimulator device 180 and the stimulation needle apparatus 100 is inposition within the patient 10 and electrically coupled to thestimulation device 180, in some examples, a trial stimulation can bedelivered. In some examples, the cannula 122 is insulated to inhibit thestimulation pulse of the trial stimulation from being conducted to thebody tissue radially outwardly through the cannula 122. In this way, thestimulation pulse is conducted from the stylet connection 150 throughthe stylet 142 to the distal stylet end 142B to administer the trialstimulation from the distal stylet end 142B to body tissue of thepatient (for instance, the location 14 in FIG. 7A). In some examples,the stimulation needle apparatus 100 is intended to be insertedproximate nerve tissue of the patient 10 or other subject. In furtherexamples, the stimulation needle apparatus 100 is intended to beinserted proximate a sacral nerve of the patient 10 or other subject.

Once the trial stimulation is administered, the patient 10 or othersubject is monitored for a response to the trial stimulation todetermine whether the stimulation needle apparatus 100 is properlyplaced with respect to the body tissue. In some examples, if thestimulation needle apparatus is at the correct location within thepatient 10 (for instance, a location 14 in FIG. 7A), a particularresponse should be noted by a physician or other caregiver performingthe procedure. In some instances, toe movement, for example, could be anindicator that the stimulator needle apparatus 100 is properlypositioned within the patient 10. Other responses, either in addition toor instead of toe movement, can indicate proper positioning of thestimulator needle apparatus 100, depending on what area or what tissue(nerve tissue, for instance) is being targeted. In some examples, animaging technique (such as fluoroscopy, for instance) can be usedinstead of or in addition to verify proper positioning of thestimulation needle apparatus 100 within the patient 10. If the properresponse from the patient 10 or other subject is not obtained with thetrial stimulation or if it is otherwise evident that the stimulationneedle apparatus 100 is not properly located within the patient 10 orother subject, in some examples, the stimulation needle apparatus 100can be repositioned within the patient 10 or other subject and anothertrial stimulation can be performed (and/or image taken). This processcan be repeated, in some examples, until the proper positioning of thestimulation needle apparatus 100 is obtained.

Once proper positioning is achieved, in some examples, the styletassembly 140 can be removed from the cannula assembly 120. In someexamples, removing the stylet 142 from within the cannula 122 includesdisengaging the stylet hub 146 from the cannula hub 126. In someexamples, the stylet hub 146 is disengaged from the cannula hub 126 bytwisting the stylet hub 146 out of engagement with the cannula hub 126.For instance, referring to FIGS. 7A and 7B, in some examples, once thestimulation needle apparatus 100 is positioned at the desired location(for instance, the location 14), the stylet assembly 140 can be rotatedin direction C with respect to the cannula assembly 120 to disengage thestylet assembly 140 from the cannula assembly 120. Once disengaged, insome examples, the stylet assembly 140 can be moved proximally withrespect to the cannula assembly 120 along direction D to remove thestylet assembly 140 from the cannula assembly 120, thereby leaving thecannula assembly 120 in place within the patient 10. As described above,the likelihood of the cannula assembly 120 migrating proximally ordistally during disengagement of the stylet assembly 140 from thecannula assembly 120 is reduced because the forces imparted to thestylet assembly 140 and/or the cannula assembly 120 for disengagement ofthe stylet assembly 140 and the cannula assembly 120 are largelyrotational and largely not directed longitudinally (proximally ordistally) with respect to the stylet assembly 140 and/or the cannulaassembly 120. In this way, in some examples, the stylet 142 can beremoved from within the cannula 122 while maintaining the location ofthe cannula 122 within the patient 10 or other subject.

Referring to FIGS. 8A and 8B, in some examples, once the stylet assembly140 is removed from the cannula assembly 120, a directional guide 190can be inserted. In some examples, the directional guide 190 includes aguidewire. In some examples, the directional guide 190 includes one ormore markings 194 to assist in positioning the directional guide 190with respect to the cannula assembly 120. For instance, in someexamples, the directional guide 190 can include a first marking 194A forplacement just proximal of a proximal end of the cannula assembly 140 toindicate that a distal end of the directional guide 190 is positioned atthe distal cannula end 122B and, in turn, at the location 14 within thepatient 10. In some examples, the directional guide 190 can include asecond marking 194B for use with another cannula assembly, such as acannula assembly with a longer cannula than the cannula 122 of thecannula assembly 120. The one or more markings 194, in some examples,allow for a visual indication that the directional guide 190 is in theproper location with respect to the cannula assembly 120 to decrease thechance that the directional guide 190 is extended distally too far withrespect to the cannula assembly 120 such that the distal end of thedirectional guide 190 extends beyond the distal cannula end 122B and, inturn, beyond the location 14 within the patient 10. In some examples,the one or more markings 194 can also allow for a visual indication thatthe directional guide 190 is in the proper location with respect to thecannula assembly 120 to decrease the chance that the directional guide190 has not been inserted far enough into the cannula assembly 120 suchthat the distal end of the directional guide 190 is left within thecannula 122 of the cannula assembly 120 and short of the location 14within the patient 10.

Referring to FIGS. 9A and 9B, once the directional guide 190 is insertedwithin the cannula assembly 120 such that the distal end of thedirectional guide 190 is positioned at the location 14 of the patient10, the cannula assembly 120 can be removed from the directional guide190. For instance, in some examples, the physician or other caregivercan hold the directional guide 190 in place with respect to the patient10 or other subject while removing the cannula assembly 120 along adirection E. With the cannula assembly 120 removed, in various examples,another component can then be inserted within the patient 10 or othersubject, for instance, over the directional guide 190, such as, but notlimited to a dilator assembly, an over-the-wire lead assembly, or thelike.

The present inventors have recognized various advantages of the subjectmatter described herein. For instance, in some examples, the stimulationneedle apparatus provides for the ability to administer a trialstimulation to a location within a patient in order to determine if thestimulation needle apparatus is properly placed with respect to thelocation. Additionally, in some examples, the stimulation needleapparatus includes a stylet connection at a proximal end of thestimulation needle apparatus to provide a relatively easily accessibleconnection point for electrically coupling a stimulation device to thestylet in order to administer the trial stimulation. Also, in someexamples, the stimulation needle apparatus includes a stylet assemblythat is able to be removed from engagement with the cannula assemblywith little to no movement of the cannula assembly with respect to thepatient or other subject. While various advantages of examples ofstimulation needle apparatuses and methods are listed herein, this listis not considered to be complete, as further advantages may becomeapparent from the description and figures presented herein.

Although the subject matter of the present patent application has beendescribed with reference to various examples, workers skilled in the artwill recognize that changes can be made in form and detail withoutdeparting from the scope of the subject matter recited in the belowclaims.

The above Detailed Description includes references to the accompanyingdrawings, which form a part of the Detailed Description. The drawingsshow, by way of illustration, specific examples in which the presentapparatuses and methods can be practiced. These embodiments are alsoreferred to herein as “examples.”

The above Detailed Description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or moreelements thereof) can be used in combination with each other. Otherembodiments can be used, such as by one of ordinary skill in the artupon reviewing the above description. Also, various features or elementscan be grouped together to streamline the disclosure. This should not beinterpreted as intending that an unclaimed disclosed feature isessential to any claim. Rather, inventive subject matter can lie in lessthan all features of a particular disclosed embodiment. Thus, thefollowing claims are hereby incorporated into the Detailed Description,with each claim standing on its own as a separate embodiment. The scopeof the invention should be determined with reference to the appendedclaims, along with the full scope of equivalents to which such claimsare entitled.

In this document, the terms “a” or “an” are used to include one or morethan one, independent of any other instances or usages of “at least one”or “one or more.” In this document, the term “or” is used to refer to anonexclusive or, such that “A or B” includes “A but not B,” “B but notA,” and “A and B,” unless otherwise indicated. In this document, theterms “about” and “approximately” or similar are used to refer to anamount that is nearly, almost, or in the vicinity of being equal to astated amount.

In the appended claims, the terms “including” and “in which” are used asthe plain-English equivalents of the respective terms “comprising” and“wherein.” Also, in the following claims, the terms “including” and“comprising” are open-ended, that is, an apparatus or method thatincludes elements in addition to those listed after such a term in aclaim are still deemed to fall within the scope of that claim. Moreover,in the following claims, the terms “first,” “second,” and “third,” etc.are used merely as labels, and are not intended to impose numericalrequirements on their objects.

The Abstract is provided to allow the reader to quickly ascertain thenature of the technical disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims.

The invention claimed is:
 1. A stimulation needle apparatus, comprising:a stylet assembly that includes: a stylet that extends along alongitudinal axis, wherein the stylet has a proximal stylet end and adistal stylet end; a stylet hub located at the proximal stylet end; anda conductive loop that is integrally formed from a same piece ofmaterial as the stylet, wherein the conductive loop is electricallycoupled to the stylet, thereby defining a two-dimensional enclosure,wherein the conductive loop is configured to engage with a stimulatordevice, such that an electrical pulse generated by the stimulator devicecan propagate to the stylet through the conductive loop, and wherein anentirety of the conductive loop extends proximally beyond a planarsurface of the stylet hub.
 2. The stimulation needle apparatus of claim1, wherein the conductive loop is configured to be hooked onto analligator clip, a pin and socket connector, or a threaded connector ofthe stimulator device.
 3. The stimulation needle apparatus of claim 1,further comprising a cannula assembly that is engageable with the styletassembly.
 4. The stimulation needle apparatus of claim 3, wherein thecannula assembly and the stylet assembly are engaged via an engagementmechanism selected from the group consisting of: a threaded engagement,a tab-in-slot connection, a bayonet connection, and a compressioncoupling.
 5. The stimulation needle apparatus of claim 3, wherein thestylet assembly is configured to: engage with the cannula assembly via afirst rotational motion; and disengage with the cannula assembly via asecond rotational motion opposite the first rotational motion.
 6. Thestimulation needle apparatus of claim 5, wherein the first rotationalmotion and the second rotational motion are relative to the longitudinalaxis and are applied at least in part via the stylet hub.
 7. Thestimulation needle apparatus of claim 3, wherein an engagement betweenthe stylet assembly and the cannula assembly is non-rotational.
 8. Thestimulation needle apparatus of claim 7, wherein the stylet assembly andthe cannula assembly are engaged using a press fit configuration or asnap-together configuration.
 9. The stimulation needle apparatus ofclaim 3, wherein the cannula assembly includes: a cannula that defines acannula lumen extending along the longitudinal axis from a proximalcannula end to a distal cannula end; and a cannula hub disposed at theproximal cannula end, wherein the cannula lumen is accessible throughthe cannula hub.
 10. The stimulation needle apparatus of claim 9,wherein the stylet is sized and shaped to fit within the cannula lumen.11. The stimulation needle apparatus of claim 9, wherein the cannulaincludes one or more depth marks.
 12. The stimulation needle apparatusof claim 11, wherein the one or more depth marks are etched or moldedinto the cannula.
 13. The stimulation needle apparatus of claim 9,wherein the cannula is electrically insulated.
 14. A stimulation needleapparatus, comprising: a stylet assembly that includes: a stylet thatextends along a longitudinal axis, wherein the stylet has a first endand a second end opposite the first end; a stylet hub located at thefirst end; and a conductive loop that is coupled to the stylet hub in amanner such that an entirety of the conductive loop extends proximallybeyond a planar surface of the stylet hub, thereby defining atwo-dimensional enclosure, and wherein the conductive loop is configuredto engage with a stimulator device, such that an electrical pulsegenerated by the stimulator device can propagate to the stylet throughthe conductive loop, wherein the conductive loop and the stylet areintegrally formed from a same piece of material, and wherein theconductive loop is configured to be hooked onto an alligator clip, a pinand socket connector, or a threaded connector of the stimulator device.15. The stimulation needle apparatus of claim 14, further comprising acannula assembly that is engageable with the stylet assembly via anengagement mechanism selected from the group consisting of: a threadedengagement, a tab-in-slot connection, a bayonet connection, and acompression coupling.
 16. The stimulation needle apparatus of claim 15,wherein the stylet assembly is configured to: engage with the cannulaassembly via a first rotational motion; and disengage with the cannulaassembly via a second rotational motion opposite the first rotationalmotion; wherein the first rotational motion and the second rotationalmotion are relative to the longitudinal axis and are applied at least inpart via the stylet hub.
 17. The stimulation needle apparatus of claim15, wherein the stylet assembly and the cannula assembly are engagedusing a press fit configuration or a snap-together configuration. 18.The stimulation needle apparatus of claim 15, wherein the cannulaassembly includes: a cannula that defines a cannula lumen extendingalong the longitudinal axis from a proximal cannula end to a distalcannula end; and a cannula hub disposed at the proximal cannula end,wherein the cannula lumen is accessible through the cannula hub;wherein: the stylet is sized and shaped to fit within the cannula lumen;the cannula includes one or more depth marks etched or molded into thecannula; and the cannula is electrically insulated and includes one ormore depth marks.
 19. A stimulation needle apparatus, comprising: astylet assembly that includes: a stylet that extends along alongitudinal axis, wherein the stylet has a proximal stylet end and adistal stylet end; a stylet hub located at the proximal stylet end; anda conductive mechanism whose entirety thereof extends proximally beyonda planar surface of the stylet hub, wherein the conductive mechanism isa single piece of structure, such that the single piece of structure andthe planar surface of the stylet hub collectively define atwo-dimensional enclosure, wherein the conductive mechanism isconfigured to be attachable to a clip or a connector, and wherein theconductive mechanism is electrically coupled to the stylet andconfigured to engage with a pulse generator, such that an electricalpulse generated by the pulse generator can propagate to the styletthrough the conductive mechanism.
 20. The stimulation needle apparatusof claim 19, wherein the conductive mechanism consists of a U-shapedconductive loop.